Nato governments are now publicly acknowledging that it might be necessary for troops to fight their way in to return and resettle refugees.
It fell to the Canadian government to be the first to admit that much of the alliance's strategy had been overtaken by events, and that ground forces might be necessary.
"The plan has been ... to bring the Yugoslav government to the table, to have a peace plan and, on that basis, for ground troops to then go in to ensure the security of the people of Kosovo," said the Canadian Defence Minister, Art Eggleton.
"Now, if that's not going to be possible, and I think as we see with each day the Milosevic government is not indicating they're favourable to doing that, then certainly Nato has to look at other options," the minister said.
"And the military planners and the Canadian military are in the course of looking at other options as to where ground troops might be involved," Mr Eggleton said.
Canada would only act alongside other Nato nations. Officials in Washington and London conceded that planning for other options was under way, despite the rhetoric.
"We have no intention of putting ground troops in to Kosovo," a US officer said at the Pentagon briefing. "I would also say that any prudent military planner probably would plan not only in this case but any case for all possibilities." Officials underlined that planning did not necessarily imply action in the short term.
Nato foreign ministers will meet on Monday to discuss their future strategy towards Kosovo, after the initial plan was overtaken by a programme of "ethnic cleansing" that resulted in a massive refugee outflow. Between now and then many options will be on the table, officials in Washington said. Nato is also planning to bring in many more aircraft to buttress the force in the region which has been attacking Yugoslavia. "We'll be looking for other augmentations coming in - reconnaissance, strike and various other means," General Wesley Clark, the Supreme Allied Commander in Europe, said in Brussels. "I want to get the job done."
Nato is also planning to rethink the idea of limiting the status of the Kosovo Albanians to autonomy.
"There is work to be done on this political solution on the basis of the Rambouillet accord. What should we adapt? What should we keep? What form should the international security measures take on the ground?" asked the French Foreign Minister, Hubert Vedrine.
One idea that is being discussed is for Kosovo to become an international protectorate, supervised by a force led by Nato but including Russian forces.